Monitoring Hardening Behavior of Cementitious Materials Using Contactless Ultrasonic Method.

Jinyoung Hong,Hajin Choi

doi:10.3390/s21103421

Abstract

We propose a novel contactless ultrasonic method for monitoring the hardening behavior of cementitious materials. The goal of this method is to obtain high-quality data to compare the unique hardening process between rapid setting cement (RSC) and ordinary Portland cement (OPC) mortars without physical coupling to the surface of the specimens. To monitor the hardening behavior of cementitious materials, conventional approaches use contact or embedded-type sensors, which limit field application. Our solution is to measure leaky Rayleigh waves at the interface between air and cementitious materials, which allows for the estimation of the physical state of the medium in real time. The modulus development was back-calculated based on the increment of wave velocity using the developed sensor array and transform-based signal processing. We experimentally demonstrated that the proposed method possibly exhibits unique hardening information about flash setting, effects of a retarder, and modulus increments from RSC specimens.

Highlights

Monitoring Hardening Behavior ofThe hardening behavior of cementitious materials, such as setting, is an important characteristic in construction sites
Overall workflow in construction is scheduled depending on the setting of cementitious materials
Based on four standards (ASTM C 191, 266, 403, and 953), empirical values based on penetration tests are used to define the setting of cementitious materials [1,2,3,4]

Summary

Introduction

The hardening behavior of cementitious materials, such as setting, is an important characteristic in construction sites. Overall workflow in construction is scheduled depending on the setting of cementitious materials. The standard definition of setting is arbitrary. Based on four standards (ASTM C 191, 266, 403, and 953), empirical values based on penetration tests are used to define the setting of cementitious materials [1,2,3,4]. The times determined for the measures in these standards are not identical [5]. Penetrating test methods are not directly applicable to fresh concrete, owing to misleading values caused by coarse aggregates. The hardening behavior of the mortar fraction is not identical to that of concrete, owing to the different compositions of the materials [6]

Methods

Results

Discussion

Conclusion